Arrow function的restore
var materials = [
'Hydrogen',
'Helium',
'Lithium',
'Beryllium'
];
console.log(materials.map(material => material.length));
标准函数形式:
var materials = [
'Hydrogen',
'Helium',
'Lithium',
'Beryllium'
];
console.log(materials.map(function(materils){
return materils.length()
}));